Field
Embodiments disclosed herein generally relate to semiconductor process equipment used to transfer semiconductor substrates.
Description of the Related Art
Semiconductor devices are typically formed on semiconductor substrates using numerous process chambers, where each process chamber is used to complete one or more of the various steps (e.g., depositions) to form the semiconductor devices, such as a memory chip. Substrate transfer systems are typically used to move the substrates between each of the process chambers. The process chambers as well as the substrate transfer system can each be held at vacuum. Two common arrangements used for substrate transfer systems include a cluster arrangement and a linear arrangement.
A substrate transfer system using a cluster arrangement includes a central region surrounded by the different process chambers. The central region can be connected to a load lock chamber in order to maintain the vacuum environment within the substrate transfer system when the substrates are supplied and removed from the substrate transfer system. The central region, or transfer chamber, also typically includes a fixed robot that rotates about a central axis to move substrates to and from the load lock chamber as well as between the process chambers. These conventional robots are often limited to only transferring one or two substrates at a time and can cause the footprint of the central region to be large, due to the need for the robot to rotate and extend into the process chambers without the robot's arms interfering with the walls of the central region chamber in which the robot resides. These types of conventional robots can also be a source of particles, which is undesirable.
A substrate transfer system using a linear arrangement typically includes a conveyor having a rectangular top surface with process chambers on one side or opposing sides of the conveyor. The conveyor can be connected to a load lock chamber in order to maintain the vacuum environment within the substrate transfer system when the substrates are supplied and removed from the substrate transfer system. One or more robots that can be positioned near each of the process chambers to transfer the substrates between the conveyor and the process chambers. The conveyors used in these linear substrate transfer systems can be a source of particle generation, and require regular and involved maintenance activities to assure that the conveyor is performing correctly. Furthermore, the conveyor can only be moved in one direction at a time, which can limit the movement of the substrates on the conveyor reducing throughput.
Therefore, there is a need for improved substrate transfer systems that have reduced particle generation and footprint as well as increased throughput.